Early noise-induced hearing loss in teenage boys.

A hearing examination of 538 teenage boys in vocational school classes--implying future on-the-job noise exposure--showed a hearing loss (greater than 20 dB HL at any frequency) in 15% of the cases. Few correlations could be demonstrated between hearing loss and specific leisure time activities. There was, however, a correlation between high frequency hearing loss in the left ear and hereditary hearing loss. The most affected frequency was 6 kHz, suggesting a noise etiology--a suggestion emphasized by the noisy hobbies of these teenagers. It cannot be excluded that a hereditary deficiency could either manifest itself as a localized dip at 6 kHz or reveal itself as an increased vulnerability to noise, identified at young age as a high frequency dip at 6 kHz.